The present invention relates generally to medical monitoring systems, and more particularly has reference to a new and improved system and method for providing an accurate and reliable indication of whether a patient in a hospital, nursing home, assisted living facility or other healthcare facility, is in bed, out of bed, or is actively attempting to exit the bed.
Monitoring patients is an important aspect of patient care in many different settings. In a general medical or surgical ward or floor of a hospital, for example, monitoring vital signs such as heart rate and respiratory rate is a basic component of patient care. Monitoring the presence or absence of a patient in his or her bed also may be beneficial in a general medical or surgical ward or other area of a hospital or healthcare facility. If certain patients leave their beds, they run a risk of falling and injuring themselves, or of becoming detached from important treatment apparatus such as IV lines, drainage tubes and like. Confused patients (e.g., those suffering from some form of mental disability), might become lost or wander off from the healthcare facility.
Current systems for patient monitoring used in most hospitals generally do not provide for constant, around-the-clock monitoring. Instead, on a general medical or surgical ward of a hospital, for example, monitoring typically consists of a team of nurses circulating from patient to patient, at three- or four-hour intervals, to take vital signs. In some hospitals, this monitoring may be augmented by one or more devices, such as a bedside pulse-oximeter, which monitors pulse and oxygen saturation via a small clamp-like device attached to a patient's finger. The method for determining whether a patient on bed restrictions actually remains in bed, often involves direct observation by a nurse or other caregiver.
Recently, some efforts have been made to develop a system for accurately measuring basic physiological parameters, such as heart rate and respiratory rate continuously, without the use of electrodes, leads or other devices that require direct attachment to the patient's body. The system is designed to utilize a signal processor with data collection sensors disposed invisibly in the patient's bed that produce an electrical signal in response to physiological patient stimuli as the patient lies in bed on the sensor device. Upon detecting a change signifying a deterioration in the patient's condition, the system is designed to notify and report the event to the care staff utilizing the hospital's existing nurse call system.
Bed exit systems of various kinds are known. Historically, physical restraints (such as vests, ankle or wrist restraints) were used to try to keep patients safe in healthcare facilities. In recent years, however, the healthcare community has come to recognize that physically restraining a patient can be dangerous. Bed rails are sometimes used as restraints, but these too have proven to be a safety concern. Additionally, some hospitals incur considerable expense to employ bed-sitters to watch patients, primarily to guard against unauthorized exiting the bed.
More recently, alarm-based systems of two types have been developed. There are bed-based systems designed to be attached to a bed or selectively deployed near a patient's bed as needed. There also are patient-applied systems, such as clips or RF sensors (bracelets) designed to be worn by the patient.
The bed-based alarm systems generally include integrated position sensor systems that are designed to be built into the bed structure in a permanent fashion. These systems are intended to be dedicated devices that generally rely on the use of advanced technology, such as load cells, capacitive sensors or resistive sensors, to sense a patient's weight and position on the bed. They tend to be costly and difficult to install and cannot be separated from the bed once they have been installed.
Pressure sensitive pad systems, on the other hand, are generally stand-alone devices intended to be selectively deployed, which require the use of obtrusive and cumbersome pads designed to be placed over a mattress, under the mattress, or on the floor near the patient's bed. Typically, these pad-type sensors are relatively small in size and provide only localized detection (e.g., one or two detection zones in the hip and occasionally shoulder areas). Typically, they are not designed for use with smaller or lighter patients or with in-bed vital signs monitoring systems.
Many of the existing pressure sensitive pad systems also are prone to false positives, i.e., the patient is in bed, but is sensed as being out of bed, resulting in unnecessary nuisance alarms that care staff must respond to. This deficiency often is due to the use of latching alarms, insufficient sensor size, insufficient sensitivity, impacts of the mattress and/or bedding, and the lack of a delay before actuating the alarm. Pad placement also tends to be critical with many of these designs, and many false alarms are caused by improper pad placement. Another drawback is the frequent occurrence of false negatives, i.e., the patient is out of bed, but is sensed as being in bed. This is a potential safety concern for a hospital patient on bed exit restrictions, as the patient may have fallen or be at risk for falling while no alert to care staff has been generated.
A need exists for an improved bed exit detection system that is more reliable than current pad systems and easier to use, but is more adaptable and less costly and complex than current integrated systems. Ideally, such a system would be capable of being retrofit to an existing hospital bed in a way that would be virtually invisible to the patient and staff. In order to enhance the work flow of nurses and other caregivers in a hospital or other healthcare facility, the system should alert reliably and accurately, and should be able to accurately detect virtually all in-bed conditions regardless of patient size, position or location in the bed (i.e., not be prone to false negatives). The system should be capable of alerting hospital staff not only when patients are out of bed when they have orders to stay in bed, but for some patients (such as slow moving patients, for example), of providing a warning before the patient actually exits the bed.
However, the general medical or surgical floor area of a hospital is a particularly challenging environment for a bed exit detection system. A system designed for use in such an environment needs to accommodate different kinds of beds, including flat beds and articulated beds (i.e., beds with articulated frame sections which can be angled upwardly in order to position the upper torso and head of the patient or the patient's feet, in a more upright fashion), and beds with full-length rails or half-length rails (i.e., rails that extend only along the upper torso portions of the bed), each of which presents possibly different bed exit scenarios. Most hospital beds in use today include some form of articulation and some form of a half-rail configuration, either a single half-rail in the torso area or split rails, i.e., two half-rails side-by-side, one in the torso area and another in the leg area, with a gap in between.
There are further factors as well which make the hospital a challenging environment for bed exit detection. Compatibility is necessary with a large variety of hospital beds and mattresses of differing size, weight and structure (e.g., a powered, fluid-filled mattress has different characteristics than a passive foam mattress). Hospital patients also come in a wide variety of sizes and weights, and while the majority of patients are supine with elevated head of bed, they may assume a variety of different positions on the bed, including side, prone or sitting positions, with the bed flat, or with the head or feet elevated. Additionally, hospital patients often sit up and eat in bed. Visitors in the patient's room provide another source of potential complications, since they might touch, lean on, or sit on the patient's bed, providing false indications. Hospital staff also tend to move or adjust the patient in the course of treatment. The presence of various kinds of bedding (such as pillows or support cushions), hospital equipment or other apparatus in the vicinity of a patient's bed also creates the risk of a foreign object on the bed that may potentially provide a false indication that a patient is present in the bed. Additionally, since hospital patients are in bed a high percentage of the time, wear and tear issues also can be a significant challenge.
Further challenges include the need for both remote and local alarms to alert the patient and care staff of possible bed exit conditions, and the need for a system which is comfortable to the patient and does not create a pressure distribution on the bed which could compromise skin integrity or the patient's health. Further, the system must be reliable, because there often is a minimal tolerance of false alarm by care staff, and should be flexible enough to accommodate the differing needs of different patients.
A bed exit system intended for use in the general medical or surgical floor area of a hospital or other institution also should be compatible with a remote in-bed vital signs monitoring system. Proper selection and relative placement of the different kinds of sensors used for vital signs and bed exit detection, respectively, thus becomes an important consideration. Ideally, means should be provided to maintain the integrity of those sensor placements, while allowing for easy adaptability to a variety of beds and bed configurations.
Thus, a need exists for a bed exit detection system suitable for use in the general medical or surgical floor areas of a hospital or other healthcare facility, which is compatible with a remote vital signs monitoring system, can be easily adapted to a variety of different kinds of beds, and which is sufficiently reliable both for in-bed and out-of-bed detection over the full range of patient positions and bed exit maneuvers commonly encountered in a hospital environment, so as to improve patient safety and care, free-up nursing staff for other important tasks, and improve overall clinical operations in the institution, all at a reasonable cost.
The present invention fulfills these and other needs.